Question: next, master and pu branches

Hello,

Can somebody explain the meaning of next and pu branches and some documenation 
about using topic branches.

My development model use two branches now: stable release and develment 
branch. All changes in the stable release branch are bug-fix only changes. 
All (or most) of them must go to development release. Now I do this using 
cherry-pick but it is not easy to track what was merged especialy when merge 
pruduce confic resloved by hands. Stable branch live long life, much more 
than 100 commits. 

It seems topic branches can help me here, but reading Documentation under git 
sources teach to make topic branch from the branch point and then merge it to 
both branches. This can work while stable branch has short life and was not 
heavily rewritten. 

If there any technique that can help me ?